b2200 brake problems
 

I've got an 87 b2200 that's having brake issues.
New Master cylinder (bench bled), new calipers, new proportioning valve and new drums. I've bled these things like 15 times or so and I still can't get the truck to stop with the pedal on the floor. The pedal as a little pressure when I'm bleeding them and even when I start the truck, but when I move it and try to stop it's goes to the floor.
Anyone have any ideas?

Did you match up the power steering pushrod depth of penetration from the old master cylinder to the new master cylinder so the freeplay remains the same? This is important, it's in the factory manual and I've found the replacement master cylinders to vary in depth where the pushrod mates up. If you don't have power brakes, then similar with that pushrod.

Also, manually adjust the rear brake adjusters to drag onto the rear drums. Then bleed again.

Thanks bro, I'll check out the pushrod on the booster. I didn't do that before. The rear adjusters have been taken care of though.